The reason we haven't had issues is because armoured vehicles are very discriminated against under the rules. However whilst the end result is probably good this is for the wrong reasons. All weapons, above small arms, have equal chances of destroying any armoured vehicle with no difference between weapon and armour allowed for. So an RPG has as much chance of knocking out an M1 as a 105mm rifled gun does a Ferret.
In an urban setting this works (albeit playing all the right notes but not neccessarily in the right order) but take it ouside into the 'Bush' and it would feel wrong.
Obviously the rules were originally intended to be an uber simple set for small scale infantry combat and most of what i've suggested here and on the posts above isn't meant as a criticism of those but rather as ways of expanding things to make a satisfying game with more scope.